Boat hull



Patented July 22, 1941 STATES PATENT OFFICE BOAT HULL J ohn Walter Inwood, McGill, Nev.

Application August 24, 1939, Serial No. 291,777

7 Claims.

The present invention relates to an improved hull design or construction for boats.`

Modern conventional type boats, capable of high and medium speed, attain such speeds by taking advantage of the planing action accomplished by shaping the bottom of the hull so that, when under way, the hull rises with a consequent reduction of wetted surface or displacement. As a result such hulls must be equipped with a skeg placed on the bottom of the hull to increase its draft so as to give stability and seaworthiness to the boat.

Furthermore, the conventional type boat traveling at high speed throws the displaced water so far to the side of the boat that there is n0 chance for it to flow back into position until long after the boat has passed, thereby losing the stern thrust obtained from the return of the displaced water.

In devising the hull of the present invention the desideratum has been to produce more surface at a more effective planing angle and tohave the planing action occur at a lower rate of speed than has been heretofore produced or proposed and, further, provide for the displaced water to ow back against the sides of the hull, thereby requiring less power to propel the boat at a given speed.

Consequently, all of the drawbacks above mentioned are overcome by the hull designedv in accordance with the present invention, wherein the bow of the hull to a point about midships or slightly forward of midships is submerged and formed to cut the water in the usual manner and from this point (that is, midships or slightly forward of midships) the bottom of the hull is formed to provide a fin which ext-ends gradually deeper into the water and becomes gradually narrower toward the stern, this n being V-shaped with its outer side surfaces preferably vertically or upwardly conveXed. The forward or broader end of this fin is preferably the width of the bottom of the hull-that is, extends from chine to chine or substantially so.

By this construction the planing action takes place at a lower speed of the boat and at a more effective angle and at least part of the water displaced by the fin, when the boat is underway, ows in behind the receding sides of the iin, thereby utilizing the stern thrust and saving power which would be required to push this l amount of water to the sides of the boat. Moreover, the wetted surface of the hull is less than that of hulls of known designs of some size, displacement and draft with skegs, thus saving power required to overcome friction'al losses.

The invention further contemplates that the aft end of the i'ln be so shaped as to allow the water to ll in without creating eddys, thereby saving power.

The shape of the iin, being a convexed V, provides ample room to mount the motor therein, lower than in the conventional type boat, producing a lower center of gravity and giving more space for deck or cabin purposes.

With the above and other objects in view as will appear as the specification proceeds, the invention resides in the sundry details of construction, combination, and arrangement of parts hereinafter more fully described and pointed out in the appended claims.

In the drawings, which show the preferred embodiment of the invention as at present devised,

Figure 1 is a side elevation of the hull of a boat constructed in accordance with the present invention;

Figure 2 is a bottom view of Figure 1;

Figure 3 is a diagram illustrating the displacement curve of the entire hull, line i therein showjing the displacement curve of the aft end of the Figure l is an elevation showing the line plan of the hull at various points thereof;

Figure 5 is a cross sectional view taken substantially on line 5 5 of Figure 1;

Figure 6 shows a cross sectional view taken substantially on line 6 6 of Fig. 1; and

Figure '7 is a View similar to Figure 2, but illustrating the lines at the juncture between the iin and the hull bottom as straight converging lines rather than slightly curved as in Figure 2.

Referring more in detail to the drawings, wherein like characters denote similar and like parts throughout the several views, I0 generally denotes the hull of a boat having a keel I l, chines l2, sides i3, bottom i4, and the stern may or may not be provided with a transom i5. The sides I3 may be formed as desired and the bottom of the hull from the bow to a point substantially midship, or slightly forward of midship, is formed in a conventional manner so as to cut the water when in progress, as shown in Figures 1 and 2.

The load-water line of the hull is substantially that of the chines I2 and is indicated by the dotted line W-W in various figures of the drawings.

The V-shaped iin i6, formed on the bottom of the hull is extended from said point at about midship, or forward of midship, and gradually extends downwardly toward the stern and its sides gradually taper from a broad forward end a to a point b at the stern of the hull. The keel II forms the apex of the V-shaped fin I6 and the downward declination of the keel, and therefore of the n I6, may be such as required for the desired draft of the boat. The aft end portion s of the keel, and therefore of the 1in, extends upwardly preferably on a curved line, to the bottom I4 of the main hull at a point forward of the stern end or, if the arrangement of the propeller and rudder (not shown) will permit, may be extended to the stern end or the transom I5.

The lines of juncture c between the fin I6 and the hull bottom I4 are preferably curved as f shown in Figure 2 or may be straight converging lines c as shown in Figure 7 and it is preferred to have the outer side surfaces of the n I6 convexed upwardly from the keel II to the lines c or c', as shown particularly in Figures 4 and 6.

the bottom of the hull which is V-shaped in plan and in cross section.

2. A boat hull having a keel and chines, sides extending above the chines, the keel sloping gradually downward from the bow to the stern portion of the hull, a bottom for the hull extending between the chines and the keel forwardly from about midships of the hull and extending from chine to chine above the keel rearwardly from about midships of the hull, a line established on the bottom of the boat on each side of the keel from points about midship of the hull adjacent each chine and extending aft to a point on the In building a boat hull embodying the present s invention the procedure may be as follows: A substantially straight keel I I is laid from bow to stern on a declination aftwards to provide for the required or desired draf-t of the boat and lines for the chines I2 are then established; the ribs are then laid to provide for the sides I3 and bottom I4 of the hull according to the type of boat desired; then points i are established on the bottom I4, one on each side of the keel and between the chines and, preferably near each of the chines, at a point substantially midships or slightly forward of midships; from these points lines c or c are established which extend to a point on the longitudinal center of the bottom I4 near or at the stern I4; then a, line s is extended upwardly from the aft end of the keel, preferably on a convex curve, to meet at the point of juncture of lines c or c; then ll in from the keel II and line s to lines c or c with a surface f; and then fill in between the lines c and c and the chines I2 with a surface y, said surfaces f and y are preferably convexed upwardly and exteriorly of the boat.

Fig. 3 is a diagram illustrating the displacement of the entire hull, d being the base or keel line and the line e being the displacement curve, the line i indicating the displacement of the aft end of the n I6. The distance from d to e or from d to 7 on any cross section indicates the relative displacement at that point. It is understood that the shape of the n as described above will produce a displacement curve at the aft end of the iin (as represented by the line 7') which is approximately straight for a distance equal to 10% or more the total length of the fin.

A boat constructed in accordance with the foregoing disclosure will accomplish all the aims and objects set out in the forepart of this specification but, of course, it is to be understood that certain changes and modifications may be made as fall within the scope of the appended claims.

That which is claimed is:

1. A boat hull having a keel and chines, sides extending above the chines, the keel sloping gradually downward from the bow to the stern portion of the hull, a bottom for the hull extending between the chines and the keel forwardly from about midships of the hull and extending from chine to chine above the keel rearwardly from about midships of the hull, a line established on the bottom of the boat on each side of the keel from points about midship of the hull adjacent each chine and extending aft to a point on the longitudinal center line of the bottom near the stern where said lines meet, and surfaces extending upwardly from the keel to said lines, whereby a gradually yaftwardly declining fin is formed on longitudinal center line of the bottom and near the stern where said lines meet, said lines being outwardly curved with respect to the center line of the hull, and convex surfaces extending upwardly from the keel to said lines whereby a gradually aftwardly declining fin is formed on the bottom of the hull which is V-shaped in plan and in cross section.

3. In a boat `adapted to produce greater speed per horse-power and .to improve sea-worthy characteristics while reducing the wetted surface area, a boat-hull including a keel extending on a gradually declining line from the bow to a point adjacent the stern of the hull and providing the center-line plane of symmetry of the hull; a fore and an aft bottom portion in contact with the water at speed; the fore-portion of said bottom having downwardly converging surfaces on opposite sides of said plane of symmetry and meeting at said keel; the aft-portion of said bottom having `an upwardly convexed surface on opposite sides of said plane of symmetry and which surfaces diverge upwardly from the keel and terminate respectively inwardly of and below the load-water line at curved lines each of which latter is on opposite sides of the plane of symmetry and which curved lines diverge from a point, that is on the said plane of symmetry above and at the aft end of the keel, to a point approximately midship and adjacent the load-Water-line where forward ends of said last mentioned surfaces merge with the adjacent surfaces of the bottom fore-portion thereby providing a continuation thereof at their junctures; and other transversely convexed surfaces in the aft-portion of the bottom extending in a general horizontal direction be- Y tween the load-water-lines on opposite sides of the hull and the adjacent upper edges of said upwardly diverging surfaces, thereby providing a hull bottom having a portion thereof substantially V-shaped in plan and in cross section with its broader end about midships thereof and tapering rearwardly to a point near the stern, the portion of the keel on said V-shaped portion merging into the keel of the fore-portion of the bottom.

4. In a boat adapted to produce greater speed per horse-power and to improve sea-worthy characteristics while reducing the wetted surface area, a boat-hull including a keel extending on a gradually declining line from the bow to the stern portion of the hull and providing the center-line plane of symmetry of the hull; a fore and an aft bottom portion in Contact with the water at speed; the fore-portion of said bottom having downwardly converged surfaces on opposite sides of said plane of symmetry and meeting at said keel; the aft-portion of said bottom having surfaces, one on opposite sides of said plane of symmetry, respectively, and diverging upwardly from the keel and terminating respectively inwardly of the load-water line at lines, each of which is on opposite sides of said plane of symmetry and which lines of termination diverge from a point on said plane of symmetry and above Ithe laft end of the keel to a point approximately midship and adjacent the load-water-line where said last mentioned surfaces merge with the surfaces of the bottom fore-portion thereby providing a continuation thereof at their junctures; and other surfaces in the aft-portion of the bottom extending between the load-water lines on opposite sides of the hull and the adjacent upper edges of said upwardly diverging surfaces, thereby providing a hull bottom having a portion thereof substantially V-shaped in plan and in cross section with its broader end about midships and tapering rearwardly .to a point near the stern.

5. In a boat adapted to produce greater speed per horse-power and to improve sea-worthy characteristics while reducing wetted surface area, a boat-hull including a keel extending from the bow to the stern portion of the hull and providing the center-line plane of symmetry of the hull; a fore bottom portion and an aft bottom portion; the aft-portion' of said bottom having surfaces, each on opposite sides of said plane of symmetry respectively, and diverging upwardly from the keel with a gradually increasing degree of divergence from their aft ends, where said ends meet, to a point approximately midship and adjacent the load-Waterlines on opposite sides of the hull and where said last mentioned surfaces merge with the surfaces of the bottom fore-portion; and other surfaces in the aft-portion of the bottom extending between the load-water lines on opposite sides of the hull and the adjacent upper edges of said upwardly diverging surfaces, thereby providing a hull bottom having a portion thereof substantially V-shaped in plan and in cross section with its broader end about midships thereof and tapering rearwardly to a point near the stern.

6. In a boat as set forth in claim 5 wherein the keel gradually slopes downwardly from bow to stern.

7. In a boat as set forth in claim 5 wherein all of said surfaces are convexed transversely with respect to the plane of symmetry of the boat.

JOHN WALTER INWOOD. 

